Living area mechanical ventilation

[meternerd]

I have a partially finished basement with a room that is presently called "storage". I'd like to be able to add it to the total square footage of the home. It has no window but is heated, insulated, smoke detector and has a closet and two entrances and exits, one of which opens to another ventilated storage area that also contains the furnace, water heater and a door to the outside. To make it a permitted living area, it needs mechanical ventilation. I don't want it as a bedroom, just an exercise equipment area. Can I exhaust the vent fan into the ventilated storage area (easy to do) or does it have to vent to the outside (much harder to do)?

 

[jdfruit]

If you had a permit for the room, then conversion to another use could be approved by the AHJ (City or County). From your description, it appears there may have been "issues" with approving what you have. Current CA Res Code R310 requires all basements to have an emergency escape and rescue opening, from you description it appears you are missing that required opening in the "storage" room you are "converting". Once you have the opening, if it is properly sized, then it can be the required ventilation to exterior. If somehow you get the AHJ to accept mechanical ventilation, it must be "whole-house mechanical ventilation system installed in accordance with the California Mechanical Code" (R303.1). The CMC generally prohibits exhausting air into rooms/spaces having combustion air needs for appliances unless special consideration is given to the natural air circulation effects on the combustion air. If you want to wade through the requirements for ventilation, get a CMC and you may change your mind on using the idea.

 

[JBI]

(2015 IRC) Section M1501.1 Outdoor discharge. The air removed by every mechanical exhaust system shall be discharged to the outdoors in accordance with Section M1506.2. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.

Exception: Whole-house ventilation-type attic fans that discharge into the attic space of dwelling units having private attics shall be permitted.

Based on the above, I'd say 'no'.

Since you asked about a 'furnace' I'm guessing forced air.

Question remains about the fuel source, which may (or may not) impact the answer...